Field of the Invention
The present invention relates to a process for preparing alkaline earth metal-complexed metal bisamides of the formula (I) from metal monoamides of the formula (II). The present invention further relates to a process for preparing alkaline earth metal monoamides of the formula (II-AE), to novel LiCl-free alkaline earth metal monoamides of the formula (II-AE-L), and to the use of these alkaline earth metal monoamides for metallation of aromatics, heteroaromatics, alkenes, alkynes and other organic compounds having activated C—H bonds.

Description of Related Art
The preparation of aromatic and heteroaromatic molecules is of great significance because of the high biological potency thereof. Consequently, these structural elements are constituents of many active pharmaceutical and agrochemical ingredients. The direct metallation of aromatics, heteroaromatics or activated C—H bonds has become established as an excellent tool for functionalization of aromatics, heteroaromatics and other organic compounds.
For this purpose, predominantly lithium alkyls or lithium amides have been used to date as bases.
As an alternative, efficient bases have been developed for metallation, especially magnesiation and zincation, of aromatics and heteroaromatics. Zinc amide or magnesium amide bases, for example Mg-TMP and Zn-TMP (TMP=2,2,6,6-tetramethylpiperidyl), complexed with lithium chloride (LiCl), for example TMPMgCl.LiCl, TMPZnCl.LiCl, TMP2Zn.2MgCl2.2LiCl, are versatile metallation reagents, as described in WO 2010/092096 or WO 2008/138946. They have high kinetic basicity coupled with very good chemo- and regioselectivities. In addition, zinc amide bases, for example, can be stored under protective gas as solutions in THF (tetrahydrofuran) for weeks, without losing their activity.
For synthesis of the bases, typically amines, for example TMP, are lithiated with equimolar amounts of butyllithium (BuLi). Owing to the high cost of BuLi, zinc amide bases are too expensive for a multitude of industrial syntheses. There is therefore still an urgent need for an alternative, preferably less expensive and/or more favourable, route to metal amide bases, especially dispensing with the use of expensive BuLi.